Seriously, being of a geeky nature I often overlook the blatently obvious and had an AHA! moment today when dicing onions. My knife (carbon steel) seemed to be dragging, so I got some pretty heavy-duty scouring powder (Sabena), laid it flat on a cutting board and polished the heck out of it.

I've been doing this with my stainless steel pans for years and they are smooth as glass, but it never occured to me to do the same for my knives.

Boy, what a difference that makes! It's not like I let them rust; in fact, I'm very careful to dry them immediately after every use (they stay sharper longer, that way, too). But there was a layer of oxidation on them causing the friction.